Sealing method and means for conductor joints



April 29 1947- AQG. 'RICHARDsoN 'l 2,419,592

' s'sALms vmamon Arm mams Fon coNnucTos roms Fnd uarcn 12v, 194s 1m/mmm Arf/Px G. imma# 'Arm Patented Apr. 29, 1947 SEALING METHOD AND MEANS FOR CONDUCTOR JOINTS Avery G. Richardson, Boonton, N. J., assignor to Federal Telephone and Radio Corporation, Newark, N. J., a corporation of Delaware Application March 12, 1943, Serial No. @178,859

ici. iti-ni The present invention relates tc conductor joints, and more particularly to a int lcd of, and apparatus for, connecting a cable to a plug or to another transmission line.

In cases Where a high-frequency cable covered with a plastic material such as Vinyliteis to joined to another cable, considerable diniculty has been experienced in :making the point of con= nection moisture-proof due to the 'nature of the plastic. If the means holding the cable is loosely applied, it may result in moisture being admitted to the end of the cable. Conversely a rigid bold ing means tightly applied may cut into the plastic covering oi the cable in an undesirable man` ner.

Accordingly, one of the objects of the present invention is to provide a cable connector in which the cable is securely positioned by a holding means which forms a moisture-proof union with the covering of the cable and at the same time avoids any cutting into or otherwise injuring the covering.

Another object of the invention is to provide a method for rendering moisture-proof the end portion of a plastic-covered electrical conductor.

A further object of the invention is to provide a coupling assembly for use in making an electrical connection, wherein a flexible thermoplastic material is forced under pressure to seal the interior of the assembly from exterior moisture.

Other objects and advantages of the invention will be apparent'from the following description and from the drawing, in which:

Fig. 1 is a longitudinal sectional view of an improved connection in accordance with the invention;

Fig. 2 is a sectional view along line 2-2 of` Fig. 1:

Fig. 3 is a perspective view of one of the parts of Fig. 1;

Fig. 4 is anend view of a modificationof Fig. 1.

In the form of the invention illustrated in Figs. 1, 2 and 3 is employed a high-frequency cable A best shown in Fig. 2. The cable A is provided with a pair of spaced conductors l and I2 respectively surrounded with individual insulating coverings I4 and' I5 which, in turn, are surrounded by separate metal sheaths I 6 and I8 which may, for example, be formed of copper braid. The two sheaths I6 and I8 may, in turn, be surrounded by a common copper braid over which the common outer thermoplastic covering 22 is formed.

Referring now to Fig. 1, the cable A is partially enclosed by a tube 23 having a flange 24. The flange 24 of tube 23 is designed for insertion in a. housing 26 having a threaded inner portion 2B- and a shoulder 3B as shown. Slidably positioned on tube 23 is a. washer 32 with a key 34 receivable by a longitudinal key-way slot 36 in housing Aends ofv conductors I0 and I2.

2t. .Also slilably positions-1.. 'tube e nut 32B having a threaded portion receivabie by the threaded portion 28 ci tbe housing.

Disposed against the shoulder 3% is a compres sion element i2 preferably formed of metal. e tween this compression element d2 and the 2t of tube 2B is a plurality plastic wa shaped members lid. The washers it and cable covering 22 are preferably composed of a vinyl resin including a suitable plasticiaing eiement. These plastic elements Sie are each provided with an opening which coniorms approximately with the' cuter crosssectional shape ci the cable A.

A plug 52 of any suitable design is receivable by the other end of housing 2E.' This plug. and its method of assembly with housing 26 forms no part of the present invention. Two prongs 50 and 5| of plug 52 receive 'respectively the A wire 48 received by a prong 53 of plug 52,is lwrapped around and soldered to the shielding' 20 of cable A. It will be observed that the plastic covering 22 is removed for a sufficient distance from the end of the cable to permit attachment of wire 48 to the shielding 20.

Fig. 3 shows the design of one of the washershaped elements 44. The number employed is determined by the thickness of the elements and the amount of plastic material necessary or desired between the members 24 and 42. The opening 54 is, of course, determined by the design of cable A, it being shown in the drawing as elliptical. However, it may obviously be of another shape, the only requirement being that the opening 54 approximates the cross-sectional shape of cable A.

To simplify manufacture, the opening defined by the shoulder 30 preferably is round. For cables of other shapes or of smaller cross-section, I provide the compression washer 42. The washer 42 has a shape which corresponds to the shape of the elements 44. The Washer 42 may be separate from the housing or it may be made integral therewith.

Fig'. 4 shows a modification of the housing 2B as viewed from the left of Fig. 1 with the cable and other coupling elements removed, In this modification the compression member 42 is omitted, the shoulder 30 being shaped so that the opening formed thereby is substantially the same as the cross-section of the cable for which the coupling is intended. It will be seen that a shoulder so formed will perform the functions of compression member 42.

In assembling the parts of Fig. l, the hanged tube 23 with its associated nut 38 and lock washer 32 is slipped over the cable A, followed by the housing 26 containing the disc-shaped'elements 44 and the compression member 42. All of these parts are drawn back from the end of the cable, a section of the plastic covering 22 is removed to permit soldering of the wire u to the shielding 20, and then the conductors II and I2, as well as the wire 48, are connected to the proper prongs in plug 52. y

When this is accomplished the housing 26 is slid back over the cable and securely joined to the plug 52. Compression member 42 is seated against shoulder 30, and the washer-shaped means 44 positioned against the compression member. Tube 23 is then -drawn up so that the flange 24 lies dat against the washer-shaped elements 44 and acts as a positioning means for the cable A. The washer 32 is placed with the key 34 in the key-way slot I6 and the nut 38 is tightened to press against the washer 32. Due to the keyed construction of the washer 32, the members 24, 44 and 42 will be subjected to pressure exerted longitudinally of the housing 26 as the nut 38 is tightened. The washer 32 prevents rotation of the nut 38 from exerting torque on the 1lange`24, thus insuring the cable and the conductor connections against injury as the nut is tightened.

Tightening of the nut 38 compresses the plastic material of the washer-shaped elements 44 within the walls of an enclosure formed by the inner surface of the housing, the flange 24, the compression element 42, and the covering of the cable. Since all of these are composed of rigid material except the covering of the cable, it follows that the two plastics will be forced together.

As the washer-shaped means 44 are formed of a plastic composed of such elements as a vinyl resin in combination with-a. plasticizer, it willfullow that a tightening of the nut 38 will cause to be pressed out of the plastic material a portion of its plasticizing content. The plasticizing portion thus separated will take the form of a thin adhesive iilm wherever the washer-shaped elements 44 are in contact with the walls of the above mentioned enclosure. Likewise an adhesive lm will be formed by this pressed-out plasticizer between the washers 44 and the cable covering 22, as Well as between the individual washers, resulting in a substantially solid, completely Water-tight union.

That section of the cable covering 22 in contact with the washer-shaped elements 44 is also under pressure. Should this cable covering 22 contain a. plasticizing element, this plasticizing content will likewise be forced out. A resulting film of plasticizer will form on the outside of the plastic covering of cable A. In all, these films will render the resulting connection impervious to any moisture attempting to reach the exposed conductors l and I2 from any point toward the cable end of the housing. It will also be noted that this pressure on the washer-shaped means 44 causes them to exert a tight grip on the cable A, and thus it will be extremely diillcult to pull or draw the cable from the housing unless the nut 38 is loosened.

It has been explained hereinbefore that a. housing having a`shoulder shaped like the one shown in Fig. 4 will permit the compression element 42 to be dispensed with, since the shoulder will then perform all the functions previously performed by the compression element. However, use of such an element permits the housing to be employed with cables having different cross-sectional shapes merely by changing to a compres` sion element having an opening corresponding to the particular cable being connected. Obviously,

the use of a housing having a fixed shoulder pattern will permit the insertion therein only of a particular style of cable.

While it is preferred to use washer-shaped elements composed of a plastic similar to that of which the cable covering is formed, it will be 0bvious that such a procedure is not essential to the successful operation of the assembly. However it is desired that the two plastics have nearly similar coefficients of expansion.

While I have described above the principles of my invention in connection with specific apparatus, and particular modifications thereof, it is to be clearly understood that this description is made only by way of example and not as a limitation on the scope of my invention as set forth in the objects of my invention and the accompanying claims.

I claim:

1. A joint seal comprising, in combination, a

washer element of vinyl resin incorporating a suitable plasticizer, said washer element being interposed between two surfaces of the joint, a water-proof film composed of said plasticizer, said lm adhering to said washer and also adhering to both said surfaces, and means for establishing said film. 2. A joint seal comprising, in combination, a washer element interposed between two surfaces of the joint, a water-proof illm adhering to said washer and also adhering to both said'surfaces, and means for establishing said illm, said means comprising a member movable along the wall of the joint to exert pressure on said washer element and thereby to extrude therefrom the iluid for creation of said water-proof film.

3. The method of providing iluid tightness along a point surface, which comprises the steps of inserting solid material adjacent said joint surface, and then extruding from said solid material a water-proof fluid material contained therein, which material, upon being extruded, forms a thin illm adhering to said solid material and also adhering to said surface.

4. The method of providing fluid tightness along a joint surface, which comprises the steps of inserting, adjacent said surface, a vinyl resin material incorporating a suitable plasticizer, and then extruding said plasticizing material in such manner as to form a thin lm adhering to said vinyl resin material and also adhering to said surface.

.AVERY G. RICHARDSON.

REFERENCES CITED The following references are of record in the le of this patentz A UNITED STATES `PA'J'EN'IS Number 

